Lake Mary Ann or Tingkkarli, previously known as Mary Ann Dam is situated about 5 kilometres (3.1 mi) north of Tennant Creek, Northern Territory, Australia, just off the Stuart Highway. It is a man-made dam where some water sports can be conducted such as swimming or canoeing, surrounded by landscaped grassy areas on one side and natural bushland on the other.

Waramungu people have lived in the area of Tingkkarli for thousands of years. After colonisation, it was pegged as mining lease GML441E by Nugget Wilson and Bill Howes and Harold Williams. Wilson and Howes named the mine 'Mary Ann' after their respective daughters Mary Jean and Wendy Ann. The nearby by watercourse then became known as Mary Ann Creek or Mary Ann Billabong.

Originally the site was investigated with a view to increase the water supply for Tennant Creek and Peko Mine in the late 1940s, and later again in the mid-1950s. In 1977, local residents proposed that a recreational dam could be constructed close to Tennant Creek. The Northern Territory Government supported the proposal and construction commenced during 1979 and 1980.

It was completed in April 1980, filled for the first time in January 1981, and was opened on 24 April 1981 by the Hon Ian Tuxworth and was originally called the Mary Ann Dam.

The dam wall measures 11 metres (36 ft) high and 143 metres (469 ft) long and contains 17,000 cubic metres (600,000 cu ft) of rockfill. The impounded reservoir covers 17.6 hectares (43 acres) and holds a maximum of 450 megalitres (16×10^ cu ft).

In 2014, a Federal Court determined seven native title claims in the area of Lake Mary Ann covering 37,000 square kilometres (14,000 sq mi).